as the time Interval and number of traps. All traps should be marked with flags 

 so that they can be easily located. ]}y using this method, the per cent reduc- 

 tion of the mouse population can be determined. 



Another method for evaluating the effectiveness of mouse control is to place 

 50 pieces (half an apple) of freshly-cut apple in active runs and mark the loca- 

 tion with a flag. These apple placements should be checked in 24 hours and the 

 number of placements that have been chewed should be recorded. Several days 

 after poisoning, apple placements should be repeated at the same locations that 

 were previously marked with flags. This method merely gives a comparative 

 picture of mouse activity before and after poisoning and should not be consid- 

 ered as a mouse population index. 



Rodent Control in Apple Storages 



In protecting apple storages from rodents, It is necessary to rid the 

 premises of rats and mice. For control purposes, these can be grouped as follows: 

 (1) rats and house mice, which normally occupy buildings; and (2) Meadow mice 

 and white- footed mice which are brought into storages with boxes of apples. 



Before harvest, anticoagulant rodent baits should be used in bait stations 

 In the storage building and all buildings located nearby. About a week before 

 harvest, a cleanup of all debris as well as lumber, boxes, bags, etc., should be 

 made. The storage should then be rodent-proofed, sealing all openings around 

 pipes, drains, and ducts with metal flashing or 'j-inch mesh hardware cloth. 

 [.Xirlng harvest, it is important to get filled boxes into the storage the same 

 day rather than leaving them out overnight. Despite all precautions taken some 

 mice will get inside the storage one way or another and they can be disposed of 

 in one of two ways . 



Fumigation with poisonous gas is an effective control but should be 

 undertaken only by an experienced, reputable operator that is insured to do this 

 type of v7ork. By doing this, the likelihood of damaging fruit can be minimized 

 and the hazard to people lessened. A list of commercial exterminators can be 

 obtained from the Entomology E)epartment at the University of Massachusetts or 

 from the Better Business Bureau. 



Baiting the storage v/ith Strychnine-treated S te amed-crushed Oa ts before 

 and as it is being filled is also effective. Although Strychnine-treated 

 Steamed Crushed Oats are not recommended for use in the orchard because they 

 are less acceptable, they do have the advantage over Zinc Phosphide-treated 

 Steamed-crushed Oats of remaining toxic under humid conditions for a longer 

 period of time. Strychnine-treated Steamed-crushed Oats can be put out in 

 combination with Zinc Phosphide-treated Steamed-crushed Oats in teaspoonful quan- 

 tities in cigar box bait stations or rolled roofing paper and placed in and under 

 the pallets and along the walls at frequent Intervals. One application of these 

 baits should last all Winter. 



Some Points to Remember 



1. Mouse control is an an nual practice because mice have great reproduc- 

 tive capacities and migration from adjacent areas is rapid. For these reasons, 

 control should be undertaken just prior to freezing conditions when the mouse 

 population is at its peak. This prevents Winter damage to trees and the popula- 

 tion is slow to recover at this time. 



2. Regardless of the cont^rol method employed, particular attention should 

 be focussed on selecting favorable weather and following the recommendations. 



